Isotopes of an element will contain the same number of protons and electrons but will differ in the number of neutrons they contain. In other words, isotopes have the same atomic number because they are the same element but have a different atomic mass because they contain a different number of neutrons
Once the atomic number of an atom is known, the number of electrons can be deduced depending on if the atom is an ion or a neutral one.
<h3>Atomic number</h3>
The atomic number of an atom is the number of protons in the nucleus of the atom.
For atoms that are neutral, that is, no net charges, the number of protons is always equal to the number of electrons. In other words, the positive charges always balance the negative charges in neutral atoms.
Thus, if the atomic number of a neutral atom is 6, for example, the proton number will also be 6. Since the proton must balance the electron, the number of electrons will also be 6.
More on atomic numbers can be found here; brainly.com/question/17274608
a) For the motion of car with uniform velocity we have ,
, where s is the displacement, u is the initial velocity, t is the time taken a is the acceleration.
In this case s = 520 m, t = 223 seconds, a =0 
Substituting

The constant velocity of car a = 2.33 m/s
b) We have 
s = 520 m, t = 223 seconds, u =0 m/s
Substituting

Now we have v = u+at, where v is the final velocity
Substituting
v = 0+0.0209*223 = 4.66 m/s
So final velocity of car b = 4.66 m/s
c) Acceleration = 0.0209 
The answer to the question is:
75m/s
Just do 25*3
Answer:
Correct answer: E total = 2,800 J
Explanation:
Given:
m = 4 kg the mass of the object
V = 20 m/s the speed (velocity) of the object
H = 50 m the height of the object above the surface
E total = ? J
The total energy of an object is equal to the sum of potential and kinetic energy
E total = Ep + Ek
Ep = m g H we take g = 10 m/s²
Ep = 4 · 10 · 50 = 2,000 J
Ek = m V² / 2
Ek = 4 · 20² / 2 = 2 · 400 = 800 J
E total = 2,000 + 800 = 2,800 J
E total = 2,800 J
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